Loss of control (LOC) eating, the subjective experience of being unable to control the type or quantity of food consumed, is a hallmark feature of adolescents with sub-threshold and full syndrome eating disorders. Youth with LOC consistently report heightened social stress and sensitivity to the rewarding properties of food. Clarifying the mechanisms by which social stress and food reward sensitivity trigger and exacerbate LOC eating is required to develop novel targeted interventions. To understand the causes of psychopathology, the National Institute of Mental Health Strategic Plan proposes that a critical focus of study should involve elucidating how neural circuitry perturbations contribute to behavioral disturbances and core psychological processes. The proposed Ruth L. Kirschstein National Research Service Award (NRSA) is a two-year program of research and training focused on the neural circuitry mediating attention biases to social threat and palatable food cues in adolescent LOC eating. Magnetoencephalography (MEG), a neuroimaging technology with both excellent temporal and good spatial resolution, allows for the dissociation of two sequenced attention bias mechanisms: 1) Early unconscious attention capture provoked by emotionally salient cues; and 2) Later continued attention deployment towards those salient stimuli that gives rise to increasingly intense uncomfortable affective states. Among 75 adolescent girls with (n=50) and without (n=25) LOC eating, the proposed project will examine neural circuit activity using MEG during social threat and palatable food cue attention bias dot probe paradigms in a randomized crossover design on 2 separate days. Following each MEG session, LOC-like eating behavior will be assessed at a well-validated laboratory test meal. These MEG- test meal sessions will evaluate hypotheses that, in response to threatening (vs. neutral) faces and palatable food (vs. neutral non-food) images, increased reported and observed LOC severity will be associated with: 1) greater relative activation in bottom-up attention circuitry during the unconscious attention capture period; and 2) blunted relative activation in top-down attention circuitry during the continued attention deployment period. In the subset of girls with LOC eating (n=50), the generalizability of neural circuitry responses during the attention bias paradigms to real-world psychological processes will be evaluated using ecological momentary assessment. Findings from the proposed study would confirm the importance of a novel attentional mechanism that at least partly explains the relationship between affect dysregulation and LOC eating. Results will also provide important new information about whether brain-behavior relationships observed in the laboratory are ecologically valid. The proposed NRSA will provide unique multidisciplinary training in conceptual and technical research skills needed to carry out this multi-modal study. The innovative integration of neuroimaging, laboratory test meals, and ecological momentary assessment will elucidate how the brain, behavior, and environment interact to contribute to the development and maintenance of disordered eating in adolescents.